If your institution uses the cumulative grade point average

If your institution uses the cumulative grade point average (GPA) system you should normally have obtained,or expect to obtain,a GPA of at least 3.5 (out of 4) or above.
这是lse官网上对gpa的要求,3.5 (out of 4)使用的什么算法?我们平常用的81算3.1,92算4.2明显就不对了是吗?